Piston



Jan. 8, 1924, 1,479,867

M. l.. MUNDAY PISTON Filed Sept. 5, 1921 Patented Jan. 8, 1924.

UNITED STATES MORGAN L. MUNDAY, OF MUNDAY, TEXAS.

PISTON.

Application led September 3, 1921. Serial No. 498,268.

To all whom t may concern:

Be it known that I, MORGAN L. MUNDAY, a citizen of the United States, residin at Munday` in the county of Knox and tate of Texas, have invented certain new and uesful Improvements in Pistons,of which the following is a specification.

This invention relates to piston construction, particularly designed for gas engines where the necessity for thorough lubrication is essential while at the same time it is important that no oil leak or be pumped into the compression or explosion chamber of the engine.

Itis well known, especially by gas engine experts, that there is, in the usual type of present day gas engines, a certain amount of oil in the form of ,a film which collects in the small space between the piston and the cylinder wall, which space, though it be only a very few thousandths of an inch, is suiiicient to permit the oil in the crank case to be forced up into the explosion chamber by the partial vacuum created in the latter chamber. l

It is. therefore, an object of the present invention to provide means for intercepting the conduit which supports this film, before the oil has reached the head of the piston.

It is a. further object of this invention to provide means for collecting the oil which has been intercepted in its How and conducting it back into the 'crank case.

It is a further object of this invention to provide means for neutralizing the atmospheric pressure in the crank case by providing vents opening into the oil collecting means above the draining means which latter conduct the intercepted oil into the said crank case.

It is a further object of this invention to provide said oil intercepting and return conducting means in proximity to the packing rings which through capillary action conduct the oil up into the combustion chamber in the ordinary internal combustion engine.

Referring now to the accompanying drawings forming a part of this specification- Figure 1 is a side elevation of my improved piston, with a portion shown in section to illustrate the adaptation of my improvement Figure 2 is a vertical section through the piston; and

Figure 3 is a vertical section through a modified form of my improvement.

Referring now specifically to the drawings by numerals of reference, 2 indicates the cylinder wall of an ordinary gas engine, 4 the piston, 6 the head, 8 the skirt or wail, and 1() the openings for the wrist pin.

In Figure 2, I have shown the piston supplied with a set of three rings, the upper two 12 being installed for pressure purposes whlle the lower one 14 acts for the purpose of producing efficient suction.

The inner wall of the lower ring groove contalnin ring 14 is flared inwardly and downwar ly to provide an annular trough 1 6 or drain gutter which at its outer portion 18 merges at 19 into the horizontal portion or lower fiange 2() of the lower ring groove. Spaced at intervals around the bottom of lthis trough 16 are a plurality of drain openings 22 which conduct the intercepted and collected oil from said trough back into the crank case. Above the normal high level of the oil in the trough 16 are arranged an annular series of vent openings 24 which permit the atmospheric pressure in the crank case to enter the trough 16 above the oil, which thereby neutralizes the atmos pheric pressure in the crank case exerted 0n the drain openings 22 permitting the oil to freely drain back into the crank case. In other words, by the provision of the ventopenings 24, the pressure in the crank cas and in the trough above the oil is equalize This trough 16 which acts as a corrugation, serves to strengthen the wall of the piston and at the same time distributes the internal strain. It also assists in receiving the side thrust of the connecting rod and maintains uniform expansion. In addition to the function of equalizing the pressure within the trough and the crank case, the vent openings 22 permit at the same time. pressure to be built up against the rear wall of the ring 14 which adds pressure to the rings forcing them with great pressure against the cylinder wall.

In Figure 3, I have shown a modified form of my invention` in which the skirt S of the piston is provided with a lower ring groove 26, which contains a ring, not shown. but which acts in conjunction with the rings 12 and 14 to seal the wall of the cylinder. This ring groove is in all respects similar to that containing the ring 14 being provided with an annular trough or drain gutter 16 having drainy openings 22 and vent openin 24 In form gsigure 3, the drain trough acts as an annular corrugation which stren thens the lower portion of the piston s irt and serves the purpose of distributing the internal strain, maintaining the skirt round and of uniform expansion. The drain trough 16 functions in a manner similar to the trough 16, and therefore it is only necessary at this point to refer to the description and operation of said trough 16.

Having thus described my invention, what I claim as new and desire to protect by Letters Patent, is:

1. A piston having a head and a skirt, ring grooves arranged in the upper portion of said skirt, rings in said grooves, an oil collecting trough in the upper portion of said skirt and an oil collecting trough in the lower portion of said skirt.

2. A piston having a head and a skirt, ring grooves arranged in the upper portion of said skirt, rings in said grooves, an oil collecting trough Varranged adjacent Said rings, a ring groove arranged in the lower portion of said skirt and an oil collecting trough communicating with said ring groove.

3. A piston having a head and depending wall, the latter provided with a plurality of ring grooves, the lowermost groove having its inner wall ared inwardly and downwardly to provide an annular trough, the

latter merging into the lower flange of said lower ring groove.

4. A piston having a head and de ending wall, the latter. provided with a p urality of ring grooves, the lowermost groove hav- `ing its inner Wall dared inwardly and downwardly to provide an annular trough, said trough having a plurality of drain vents therein and merging into the lower Bange of said lower ring groove.

5. A piston having a head and depending wall, the latter provlded with a plurality of ring grooves, the lowermost groove having its innermost wall flared inwardly and downwardly to provide an annular oil collecting trough, said trough having a plurality of drain vents therein and merging into the lower Bange of said lower ring groove, said depending wall provided p with means for admitting air to said trough.

6. A plston having a head and depending wall, the latter provided with a plurality of ring grooves, the lowermost groove having its inner wally iared inwardly and downwardly to provide an annular oil collecting trough, said trough merging into the lower liange of said lower ring groove and provided with a plurality of drain vents therein, and the depending wall provided with a series of air vents in close proximity to the inner wall of the lowermost groove and communicating with the interior of said trough.

In testimony whereof I affix my signature.

MORGAN L. MUN DAY. 

